The objective of the proposed research is to obtain descriptive physiological information on the nature of compensatory speech production. Procedures involve altering the size and shape of oral structures by experimental alveolarpalatal prostheses, to be worn by normal subjects for several weeks, so that speech adaptation can occur. Measurement of speech characteristics involve simultaneous recording of the voice and articulatory activity of the mandible, tongue, and larynx using recently developed ultrasonic, strain-gauge, and palatographic monitoring techniques. Analysis will be in terms of changes in spatial and temporal articulatory patterns and acoustic characteristics of speech, induced by the dental appliances. The information obtained should provide a broader theoretical basis for understanding the phonetic consequences of dental appliance design.